Have Node::document() return a reference instead of a pointer

Source/core/page/DOMSelection.cpp

 /*
  * Copyright (C) 2007, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 42 matching lines @@
     if (!node)
         return 0;
 
     if (!node->isInShadowTree())
         return 0;
 
     return frame->document()->ancestorInThisScope(node);
 }
 
 DOMSelection::DOMSelection(const TreeScope* treeScope)
-    : DOMWindowProperty(treeScope->rootNode()->document()->frame())
+    : DOMWindowProperty(treeScope->rootNode()->document().frame())
     , m_treeScope(treeScope)
 {
     ScriptWrappable::init(this);
 }
 
 void DOMSelection::clearTreeScope()
 {
     m_treeScope = 0;
 }
 
@@ skipping 300 matching lines @@
         es.throwDOMException(IndexSizeError, ExceptionMessages::failedToExecute("getRangeAt", "Selection", String::number(index) + " is not a valid index."));
         return 0;
     }
 
     // If you're hitting this, you've added broken multi-range selection support
     ASSERT(rangeCount() == 1);
 
     if (Node* shadowAncestor = selectionShadowAncestor(m_frame)) {
         ContainerNode* container = shadowAncestor->parentNodeGuaranteedHostFree();
         int offset = shadowAncestor->nodeIndex();
-        return Range::create(shadowAncestor->document(), container, offset, container, offset);
+        return Range::create(&shadowAncestor->document(), container, offset, container, offset);
     }
 
     const VisibleSelection& selection = m_frame->selection()->selection();
     return selection.firstRange();
 }
 
 void DOMSelection::removeAllRanges()
 {
     if (!m_frame)
         return;
@@ skipping 61 matching lines @@
     setBaseAndExtent(selectedRange->startContainer(ASSERT_NO_EXCEPTION), selectedRange->startOffset(), selectedRange->startContainer(), selectedRange->startOffset(), ASSERT_NO_EXCEPTION);
 }
 
 bool DOMSelection::containsNode(const Node* n, bool allowPartial) const
 {
     if (!m_frame)
         return false;
 
     FrameSelection* selection = m_frame->selection();
 
-    if (!n || m_frame->document() != n->document() || selection->isNone())
+    if (!n || m_frame->document() != &n->document() || selection->isNone())
         return false;
 
     unsigned nodeIndex = n->nodeIndex();
     RefPtr<Range> selectedRange = selection->selection().toNormalizedRange();
 
     ContainerNode* parentNode = n->parentNode();
     if (!parentNode)
         return false;
 
     TrackExceptionState es;
@@ skipping 61 matching lines @@
         return position.computeOffsetInContainerNode();
 
     return adjustedNode->nodeIndex();
 }
 
 bool DOMSelection::isValidForPosition(Node* node) const
 {
     ASSERT(m_frame);
     if (!node)
         return true;
-    return node->document() == m_frame->document();
+    return &node->document() == m_frame->document();
 }
 
 } // namespace WebCore